EXCHANGE 


TELLURIUM 

Jl  Spectrographic  Study 


Ernest  Victor  Jones,  M.A. 


PRESENTED  TO  THE  FACULTY  OF  VANDERBILT 

UNIVERSITY  AS  A  THESIS  FOR  THE 

DEGREE  OF  DOCTOR  OF 

PHILOSOPHY 


TELLURIUM 

JI  Spectrographic  Study 


Ernest  Victor  Jones,  M.A. 


PRESENTED  TO  THE  FACULTY  OF  VANDERBILT 

UNIVERSITY  AS  A  THESIS  FOR  THE 

DEGREE  OF  DOCTOR  OF 

PHILOSOPHY 


A:  ••:>':•"•'•::'  :  -V-  .  / 


ACKNOWLEDGMENT. 


I  WISH  to  express  my  sincere  gratitude  and  thanks  to  Dr. 
William  L.  Dudley,  of  this  University,  and  his  able  corps  of 
assistants  for  their  cooperation  and  support  in  this  work.  I  am 
especially  indebted  to  Dr.  Dudley  for  his  enthusiastic  interest  in  and 
careful  direction  of  my  work,  and  to  Mr.  Paul  C.  Bowers  for  his 
valuable  aid  in  manipulating  apparatus  and  in  other  ways. 


4693 VI 


MY  BELOVED  WIFE 

EUNICE  BETH  VAUGHAN 

WHOSE  ENTHUSIASTIC  CO-OPERATION  AND  SYMPATHETIC 
HELPFULNESS  HAVE  BEEN  MY  CHIEF  IN- 
SPIRATION TO  GRADUATE 
STUDIES 


CONTENTS. 

PAGH. 

Introduction  9 

The  Object  of  This  Study 13 

Materials  Used  13 

The  Apparatus   14 

The  Comparator 15 

The  Electrodes  15 

Plan  of  Investigation  17 

The  Comparator  Method 17 

Methods  of  Procedure 18 

Results  and  Conclusions 24 

The  Spark  Spectrum  of  Tellurium 27 

Summary    32 


INTRODUCTION. 

IN  1869  Mendeleeff,1  in  announcing  the  periodic  law,  pointed 
out  that  the  atomic  weight  of  an  element  can  sometimes  be  cor- 
rected as  soon  as  its  properties'  are  known,  and  he  said  that  the 
atomic  weight  of  tellurium  must  be  not  128,  as  it  was  then  given, 
but  123  to  126.  This  statement  at  once  suggested  a  problem  which 
challenged  the  attention  of  a  number  of  chemists,  and  has  since 
been  the  subject  of  many  researches.  Various  theories  have  been 
advanced  to  explain  the  anomalous  position  of  tellurium  in  the 
periodic  system.  Tellurium,  from  a  consideration  of  its  general 
properties,  falls  into  Group  VI.,  Series  VII.',  of  the  periodic  table. 
Its  atomic  weight,  however,  now  given  as  127.5,  *s  higher  than 
that  of  iodine,  which  is  found  in  Group  VII. ,  Series  VII.,  with  an 
atomic  weight  of  126.92,  which  fact  is  out  of  harmony  with  the 
principles  upon  which  the  periodic  table  was  constructed.  With 
few  exceptions,2  the  solution  of  this  problem  has  been  sought  in 
the  direction  indicated  by  Mendeleeff — namely,  the  lowering  of  the 
atomic  weight  of  tellurium. 

After  an  investigation  extending  over  a  period  of  six  years, 
Brauner3  first  reported  his  conclusions  in  1889.  He  held  that  tel- 
lurium is  undoubtedly  a  complex  substance,  probably  a  mixture 
of  three  elements,  as  is  the  case  with  gadolinium.  The  same 
year  that  Brauner's  report  appeared,  a  theory  was  advanced  by 
Griinwald,4  who  argued  that  the  coincidence  in  certain  lines  in 
the  ultra-violet  spectra  of  tellurium,  copper,  and  antimony  pointed 
to  a  common  impurity  in  these  three  elements.  This  impurity  he 
thought  to  be  an  unknown  element  of  the  tellurium  group,  with 
an  atomic  weight  of  about  212.  This  view  was  strengthened  by 
Mendeleeff,5  who  in  1889,  in  illustrating  the  prediction  of  new 
elements  through  the  periodic  law,  outlined  briefly  the  properties 
of  an  unknown  element  which  he  called  dvitellurium.  He  as- 
signed to  it  an  atomic  weight  of  212  and  placed  it  in  the  tellurium 

'Ber,  13,  1799- 

2Zeit.  Anorg.  Chem.  12,  98. 

3Jour.  Chem.  Soc.  55,  382. 

4Monatsh.  10,  829;  Abs.  Jour.  Chem.  Soc.  58,  434. 

6Jour.  Chem.  Soc.  55,  649. 


[10] 

group.  In  1895  Brauner,1  who  had  continued  the  work  previously 
cited,  using  larger  amounts  of  tellurium  and  better  methods  of 
purification,  said :  "I  conclude  that  it  is  very  improbable  that  the 
abnormally  high  atomic  weight  of  tellurium  is  due  to  an  admix- 
ture of  a  higher  homologue  of  tellurium  having  the  atomic  weight 
of  214."  He  suggested  as  a  more  probable  theory  that  the  ordi- 
nary tellurium  (like  didymium)  consisted  of  "equal  parts  (atoms) 

of  true  telkirium  and  tetrargon,  for  —         —^=127.7."      He  pointed 

out  as  a  significant  fact  that  a  contemporary2  had  arrived  at 
identically  the  same  conclusion  from  an  entirely  different  view- 
point by  a  process  of  reasoning  based  on  certain  laws  of  harmony 
of  spectral  lines.  Standenmeyer8  reported  during  the  same  year 
(1895)  that  fractional  crystallization  of  telluric  acid  gave  no  evi- 
dence of  breaking  down  the  tellurium.  A  similar  conclusion  was 
reached  by  Norris,  Fay,  and  Edgerly4  in  1899  through  fractional 
crystallization  of  potassium  brom-tellurate.  Later  and  more  ex- 
tensive work  by  Norris5  confirmed  this  conclusion. 

Koethner6  in  1901  departed  somewhat  from  the  ordinary 
methods  of  procedure  in  applying  the  spectrograph  as  a  test  of 
the  purity  of  the  tellurium  compounds  prepared  by  the  methods 
previously  used,  and  declared  that  probably  no  investigator  had 
yet  succeeded  in  getting  absolutely  pure  tellurium.  He  found 
characteristic  lines  in  the  spectra  of  the  preparations  by  BraunerV 
and  Staudenmeyer's7  methods,  indicating  traces  of  copper,  anti- 
mony, silver,  arsenic,  and  gold.  In  a  like  manner  the  prepara- 
tions by  Norris,  Fay,  and  Edgerly's7  method  showed  traces  of  sil- 
ver and  copper  even  after  numerous  recrystallizations.  Koeth- 
ner succeeded  in  separating  all  traces  of  known  elements  from 
tellurium  and  recommended  as  a  very  satisfactory  process  the 
redistillation  under  9-12"""  pressure  of  the  product  obtained  by 
reducing  with  sulphur  dioxide  the  recrystallized  basic  nitrate  of 
tellurium.  This  tellurium,  however,  which  was  probably  of  the 
highest  degree  of  purity  yet  attained,  he  found  to  exhibit  in  its 
ultra-violet  spectrum  a  number  of  lines  coincident  with  lines  in 
the  spectra  of  copper,  antimony,  thallium,  and  indium.  These 

1Jour.  Chem.  Soc.  67,  549.  5Jour.  Amer.  Chem.  Soc.  28,  1675. 

2Compt.  rend.  120,  361.  "Ann.  319,  I, 

3Zeit.  Anorg.  Chem.  10,  189.  7Loc.  cit. 
*Amer.  Chem.  Jour.  23,  105. 


[11] 

coincident  lines  were  shown  also  by  tellurium  obtained  from 
SteinerV  diphenyl  telluride  of  constant  boiling  point,  which  was 
free  from  all  known  impurities,  as  shown  by  the  spectrograph. 
These  were  not  characteristic  lines,  but  they  did  not  change  in 
appearance  in  the  least  throughout  the  various  processes  of  puri- 
fication. No  record  is  given  of  their  wave  length  determinations. 
Koethner  did  not  agree  with  Griinwald2  in  attributing  these  co- 
incident lines  to  a  common  impurity  in  these  elements.  His  con- 
clusions were  that  these  elements  must  be  regarded  as  having 
certain  properties  in  common,  and  that  he  had  obtained  tellurium 
free  from  all  impurity.  Gutbier3  in  1905  tried  a  new  method 
similar  to  Koethner's,  but  concluded  that  no  change  ffad  been 
produced  in  the  atomic  weight  of  tellurium.  Two  years  later 
Baker  and  Bennett,4  after  extensive  investigations  of  tellurium 
covering  thirteen  years,  declared  in  favor  of  elementary  tellurium 
with  an  atomic  weight  of  127.6.  In  the  same  year  (1907)  Marck- 
wald,5  by  several  hundred  recrystallizations  of  telluric  acid,  ob- 
tained 20  fractions  which  agreed  perfectly  in  properties,  thus  in- 
dicating uniform  composition  for  tellurium.  However,  his  value 
for  atomic  weight — 126.85 — was  lower  than  that  usually  given. 
He  repeated  his  atomic  weight  determinations  by  a  volumetric 
method,6  which  he  considered  more  accurate,  and  got  a  mean 
value 'of  127.61.  Browning  and  Flint7  in  1909,  using  hydrolysis 
of  a  hydrochloric  acid  solution  of  tellurium  tetrachloride,  got 
some  very  interesting  results.  Two  fractions  were  obtained 
which  were  designated  as  alpha  (the  more  easily  hydrolyzed 
part)  and  beta  (the  part  remaining  in  the  solution).  The  alpha 
fraction  gave  an  atomic  weight  of  126.53,  and  the  beta  fraction 
an  atomic  weight  of  128.97.  These  results  were  confirmed  by 
three  methods  of  atomic  weight  determinations.  Viewed  in  the 
light  of  Brauner's  conclusions  and  Mendeleefs  predictions,  these 
results  are  exceedingly  interesting.  Flint8  continued  this  work, 
making  ten  fractionations  by  hydrolysis  of  the  tetrachloride  solu- 
tion, and  got  fractions  of  the  more  easily  hydrolyzed  tellurium, 
which  exhibited  a  progressive  diminution  of  the  atomic  weight. 
The  last  fraction,  of  more  than  20  grams,  gave  by  the  basic  ni- 

aBer.  34,  570.  5Ber.  40,  4730. 

2Loc.  cit.  6Ber.  43,  1710. 

3Ann.  342,  266.  7Amer.  Jour.  Sci.  28,  347. 

*Jour.  Chem.  Soc.  91,  1849.  8Amer.  Jour.  Sci.  30,  209. 


[12] 

trate  method,  as  a  mean  of  seven  determinations,  an  atomic  weight 
of  124.3.  The  final  residue  from  the  less  easily  hydrolyzed 
portions  was  reported  as  containing  a  small  amount  of  an  un- 
identified substance  very  similar  to  tellurium,  though  not  identical 
with  it  in  its  properties. 

The  preceding  pages  give  a  brief  survey  of  the  more  important 
investigations  of  the  abnormalities  of  tellurium  that  had  been  made 
up  to  the  time  of  beginning  the  investigation  herein  described.1 
The  general  consensus  of  opinion  favored  the  elementary  state  of 
tellurium  with  127.5  as  the  accepted  figure  for  its  atomic  weight. 

However,  the  work  of  Marckwald2  in  1907,  of  Browning  and 
Flint2  in  1909,  and  especially  of  Flint8  in  1910,  indicated  that  the 
question  of  the  homogeneity  of  tellurium  was  not  as  yet  finally 
settled.  The  success  of  Koethner2  with  the  spectrograph  made  it 
seem  worth  while  to  again,  in  the  light  of  recent  developments, 
make  use  of  the  spectrograph  in  an  investigation  of  the  complexity 
of  tellurium. 

1  While  this  work  was  in  progress  Harcourt  and  Baker  (Chem.  News,  104, 
260)  reported  some  recent  work  on  tellurium.  They  repeated  Flint's  method 
of  fractionation  by  hydrolysis,  which  gave  him  tellurium  with  a  low  atomic 
weight,  124.32,  as  determined  by  the  basic  nitrate  method.  They,  however, 
used  the  tetra-bromide  method  for  determining  the  atomic  weight,  and  got 
the  usual  value,  127.54.  They  discussed  Flint's  work  and  attributed  his 
low  atomic  weight  to  the  presence  of  tellurium  trioxide  in  his  tellurium 
dioxide,  the  weight  of  which  was  used  in  calculating  the  atomic  weight. 

2Loc.  cit. 


- 
• 


THE  OBJECT  OF  THIS  STUDY. 

1.  To  test  some  tellurium  purified  in  this  laboratory. 

2.  To  make  a  comparative  study  of  the  products  of  fractional 
precipitation  of  tellurium   from  a  hydrochloric  acid  solution  of 
tellurium  tetrachloride  by  hydrazine  hydrochloride. 

3.  To  investigate  very  carefully  the  final  residues. 

4.  To  study  minutely  the  ultra-violet  spectrum  of  tellurium. 

MATERIALS  USED. 

The  tellurium  which  formed  the  basis  of  this  investigation  was 
obtained  as  crude  tellurium  dioxide  from  the  Baltimore  Copper 
Smelting  and  Refining  Company  and  purified  in  this  laboratory 
by  Dr.  Dudley  and  Mr.  Bowers  in  the  following  manner : 

The  silica  present  was  dehydrated  and  removed  by  repeated 
evaporation  to  dryness  of  a  hydrochloric  acid  solution  of  the  crude 
material  and  the  tellurium  dioxide  finally  dissolved  in  hydro- 
chloric acid.  The  selenium  was  removed  by  fractional  precipita- 
tion with  sodium  sulphite  in  a  cold  acid  solution.  The  selenium 
came  down  first  and  was  filtered  off.  The  tellurium  was  thrown 
out  of  a  hot  acid  solution  by  adding  sodium  sulphite  until  most 
of  the  acid  had  been  neutralized  and  passing  sulphur  dioxide  into 
the  hot  solution.  The  precipitated  tellurium  was  oxidized  with 
nitric  acid  and  evaporated  to  dryness  twice  with  hydrochloric 
acid  and  taken  up  in  the  least  possible  excess  of  hydrochloric  acid 
and  filtered.  Any  silver  present  was  left  on  the  filter  as  the  chlo- 
ride. The  tellurium  was  precipitated  again,  as  above,  with  sodium 
sulphite  and  sulphur  dioxide,  filtered  by  inverse  filtration,  digested 
with  hydrochloric  acid  (i  to  i),  and  washed  by  inverse  filtra- 
tion with  ammonia-free  water  until  all  the  acid  was  removed.  It 
was  then  converted  into  basic  nitrate  by  treating  it  with  nitric 
acid  (sp.  gr.  1.25)  and  crystallized  out  by  evaporation  at  70 
degrees  centigrade.  Part  of  the  nitrate  was  recrystallized  from 
nitric  acid ;  but  owing  to  great  difficulty  in  getting  it  all  to  dissolve 
in  nitric  acid  this  process  was  abandoned  and  the  nitrate  was  heat- 
ed carefully  in  a  porcelain  crucible  to  convert  it  into  the  dioxide. . 
The  dioxide  was  reduced  and  the  tellurium  distilled  and  redistilled 
by  heating  to  dull  redness  in  a  porcelain  boat  within  a  silica  tube 
while  a  current  of  dry  hydrogen  gas  was  passing  through  the  tube. 


[14] 


The  hydrazine  hydrochloride  was  prepared  from  hydrazine  sul- 
phate by  adding  a  very  slight  excess  of  barium  chloride  and  pre- 
cipitating the  excess  of  barium  by  carefully  adding  dilute  sulphuric 
acid.  Only  Kahlbaum  chemicals  and  ammonia-free  water  were 
used. 

THE  APPARATUS. 

The  spectrograph  used  in  this  study  is  an  excellent  Style  C 
quartz  spectrograph,  made  by  the  A.  Hilgar  (Limited)  Optical 
Works  at  London.  It  consists  of  two  quartz,  lenses  of  24-inch 
focus  and  a  dispersion  system  of  one  Cornu  quartz  prism.  This 
gives  a  spectrum  of  wave  lengths  from  8,000  to  1,900  tenth- 
meters,  which  is  recorded  on  a  photographic  plate  4x10  inches 
in  size,  carried  in  a  plate  holder  which  can  be  shifted  by  means 
of  a  thumbscrew  so  that  one  plate  may  be  exposed  in  a  dozen 
different  positions.  A  section  of  a  quartz  cylinder  is  used  to  focus 
the  light  in  a  sharp  line  on  a  vertical  slit  regulated  by  a  microm- 
eter screw.  By  modifying  the  slide  for  the  slit,  as  indicated  in 


A 


r     % 


Figures  I  and  2,  it  was  made  possible  to  photograph  seven  spectra 
in  each  position  so  that  as  many  as  84  spectra  may  be  photo- 
graphed on  a  single  plate.  By  shifting  the  old  form  of  slide 
from  position  A  to  position  B  the  slit  at  ^  would  be  shortened 
from  a  a  to  b  b'.  By  shifting  the  new  form  of  slide  we  expose 
different  parts  of  the  slit  at  openings  a,  b,  c,  d,  e,  f,  and  g,  and 
thus  make  seven  exposures,  one  above  the  other,  without  moving 
the  plate.  This  proved  very  useful  in  comparing  the  spectra  of 


[15] 

the  different  elements  and  of  the  different  fractions  of  tellurium, 
since  it  made  the  spectra  so  narrow  that  four  could  be  brought  at 
the  same  time  into  the  field  of  the  comparator  microscope. 

The  photographic  plates  used  were  Cramer's  Special  Spectrum 
Plates,  sensitive  throughout  the  entire  spectrum,  and  Cramer's 
Crown  Plates,  specially  sensitive  in  the  ultra-violet  region.  About 
seven  hundred  photographs  of  spectra  were  examined  in  this  in- 
vestigation. 

THE  COMPARATOR. 

The  instrument  used  is  of  the  usual  type.  It  consists  of  two 
low-power  microscopes  firmly  mounted  six  inches  apart.  Be- 
neath these  is  a  movable  stage  which  carries  under  the  right-hand 
miscroscope  a  scale  graduated  in  tenths  of  a  millimeter,  and  under 
the  microscope  on  the  left  a  table  for  holding  the  plates.  The 
plates  were  cut  in  four  parts  and  the  pieces  placed,  one  at  a 
time,  on  the  table  under  the  left-hand  microscope,  and  the  relative 
positions  of  the  spectral  lines  read  off  on  the  scale  under  the 
right-hand  microscope  as  the  stage  was  moved  along.  These 
scale  readings  were  used  in  determining  the  wave  lengths,  as  ex- 
plained later  in  this  paper. 

THE  ELECTRODES. 

Since  tellurium,  especially  in  a  finely  divided  state,  is  very 
easily  oxidized,  the  making  of  the  electrodes  becomes  somewhat 
difficult.  The  following  method,  suggested  by  Dr.  Dudley,  works 
very  successfully : 

A  piece  of  glass  tubing  (a,  Fig.  3)  about  35  centimeters  long 
and  of  ynm  bore  was  plugged  with  loosely  packed  asbestos  (b) 
about  5  centimeters  from  one  end.  The  precipitated  or  powdered 
tellurium  (c)  was  placed  in  this  tube,  and  the  tube  was  then 
clamped  in  a  vertical  position  and  the  lower  end  connected  with 
a  hydrogen  generator.  After  all  the  air  had  been  expelled,  the 
tellurium  was  fused  by  carefully  heating  the  tube  up  to  a  temper- 
ature just  below  dull  redness.  It  was  found  that  the  tellurium 
did  not  stick  to  the  glass  tube  if  the  fusion  began  at  the  bottom. 
When  the  tellurium  had  cooled  just  below  the  fusion  point,  the 
glass  tube  was  shattered  by  throwing  a  fine  stream  of  water  on  it 
so  that  the  glass  could  be  picked  off  without  breaking  the  tel- 
lurium rod.  Sometimes  the  tellurium  could  be  pushed  out  of  the 
tube  without  picking  the  glass  to  pieces. 


[16] 

A  special  electrode  (Fig.  4)  was  used  for  sparking  ammonium 
nitrate  to  get  standard  lines  and  also  for  making  comparisons  of 
tellurium  with  various  solutions  where  solid  electrodes  could  not 
be  obtained.  The  electrode  consisted  of  a  glass  tube  (a)  through 
which  a  platinum  wire  (b)  with  a  gold  tip  (c).  was  passed.  An- 
other gold  rod  (d)  was  brought  into  position  above  the  gold  tip, 
and  the  spark  passed  between  the  rod  and  the  tip.  Solutions  of 
nitrates  of  substances  whose  spectra  were  desired  were  placed  in 
the  cup  O),  and  they  were  drawn  up  the  gold  tip  (c)  and  got 
into  the  spark  so  that  their  lines  appeared  in  the  spectra,  in  addi- 
tion to  gold  and  air  lines. 


Fig.  4. 


The  spark  was  furnished  by  a  condenser  consisting  of  four 
plates  prepared  especially  for  this  work  by  Dr.  Dudley,  using 
bakelite  as  the  dielectric.  The  plates  are  about  40  centimeters 
square  and  4.5  millimeters  thick.  The  condenser  was  charged  by 
an  induction  coil  carrying  a  current  of  2.5  amperes  under  a 
pressure  of  about  20  volts  supplied  by  nine  storage  cells  in  series. 


[17] 

PLAN  OF  INVESTIGATION. 

1.  Since  Koethner1   found  traces  of  copper,  antimony,  silver, 
gold,  and  arsenic  in  so-called  chemically  pure  tellurium,  it  was 
determined  to  make  a  very  careful  study  of  the  spectrum,  in- 
cluding wave  length  determinations,  of  the  tellurium  purified  in 
this  laboratory  to  see  if  it  was  free  from  these  elements. 

2.  The  extraordinary  results  of  Flint1  by  a  process  of  fraction- 
ation  led  to  the  adoption  of  the  following  plan :  The  tellurium  was 
to  be  fractionally  precipitated  from  hydrochloric  acid  solution  of 
tellurium  tetrachloride  by  using  hydrazine  hydrochloride.     The 
spectra  of  the  several  fractions  were  to  be  compared  in  order  to 
note  any  changes  in  the  spectra  as  a  higher  degree  of  purity  was 
attained. 

A  second  investigation  of  these  fractions — not  embraced  in  this 
paper,  but  carried  on  in  this  laboratory  by  Mr.  Bowers  under  the 
direction  of  Dr.  Dudley — was  to  be  made  by  determining  the 
atomic  weight  of  tellurium  from  the  different  fractions.  The  re- 
sults of  the  two  methods,  if  harmonious,  should  afford  a  good 
basis  for  judging  the  merits  of  Flint's  work  and  furnish  additional 
evidence  on  the  character  of  tellurium. 

3.  It  was  noted  in  reviewing  Flint's  work  that  he  reported  a 
small,  amount  of  an  unidentified  substance  in  the  final  residues. 
The  amount  was  too  small  to  admit  of  thorough  chemical  investi- 
gation.    It  was  our  plan  to'  make  a  careful  chemical  study  of  the 
final  residues  and  apply  the  spectrograph  for  the  purpose  of  iden- 
tifying any  unidentified  residues  or  precipitates  which  might  ap- 
pear. 

4.  The  coincident  lines  in  the  spectra  of  tellurium,  copper,  and 
antimony,  and  of  tellurium,  thallium,  and  indium,  were  to  be  iden- 
tified by  photographing  their  spectra  one  above  the  other.     The 
wave  lengths  of  these  lines  were  to  be  determined  by  the  com- 
parator method  described  below. 

THE  COMPARATOR  METHOD. 

The  comparator  is  used  to  get  the  relative  positions  of  the  lines. 
In  order  to  do  this  some  line  or  series  of  lines  must  be  chosen  as 
a  standard.  For  example,  in  the  spectrum  of  gold  there  are  three 
easily  recognized  lines,  which  read  as  follows:  66.000,  71.270,  and 

^oc.  cit. 


[18] 

73-6io.  Having  "set"  the  comparator  by  these  three  standards, 
the  other  lines  are  read  in  either  direction.  These  comparator 
readings  must  now  be  converted  into  wave  lengths.  This  is  done 
by  plotting  a  curve  on  coordinate  paper  in  the  following  manner : 
The  comparator  readings  of  the  easily  recognizable  lines  in  the 
copper  spectrum  are  carefully  noted  and  recorded.  Their  wave 
lengths  are  then  taken  from  a  table  of  wave  lengths.  The  lines 
whose  comparator  readings  are  32.080,  33.060,  and  37.275  have 
the  wave  lengths  4062.9,  4022.9,  and  3860.6,  respectively.  The 
comparator  readings  are  now  measured  along  the  horizontal  co- 
ordinate and  wave  lengths  along  the  vertical  coordinate.  (See 
Fig.  5.)  Then  using  as  coordinates  the  comparator  reading  and 
wave  length  of  each  line  —  e.  g.,  32.080,  4062.9 ;  33.060,  4022.9, 
etc. — we  locate  a  series  of  points  through  which  the  curve  is 
drawn.  To  find  the  wave  length  of  an  unknown  line,  take  its 
comparator  reading  and  locate  the  point  corresponding  to  this 
reading  on  the  horizontal  coordinate  and  there  erect  a  perpendicu- 
lar, and  from  the  point  at  which  it  cuts  the  curve  drop  another 
perpendicular  to  the  vertical  coordinate,  and  read  off  the  wave 
length  on  the  vertical  coordinate.  The  error  of  this  ^method  is 
about  0.5  Angstrom  unit  for  sharply  defined  lines. 

METHODS  OF  PROCEDURE. 

1.  A  large  number  of  spectra  of  the  tellurium  purified  in  this 
laboratory  were  photographed,  and  the  wave  lengths  of  the  lines 
present  were  determined  by  the  comparator  method.     Tables  of 
wave  lengths  were  then  consulted  to  discover  any  lines  indicating 
the  presence  of  an  impurity.     The  spectra  of  tellurium,  copper, 
antimony,  and  gold  were  compared  by  photographing  them  one 
above  the  other.     At  first  no  impurities  were  detected.     But  by 
using  heavy  voltage  on  the  induction  coil  and  reducing  the  re- 
sistance in  the  spark  circuit  to  a  minimum  a  much  fatter  spark 
was  obtained  which  brought  out  the  two  copper  lines  mentioned 
by  Koethner1 — A3273-4  and  A3246.8.     In  this  connection  it  was 
noted  that  Watt's  table  of  wave  lengths  gives  these  lines  as  10 
tellurium  lines.     They  are  not  present  in  the  spectrum  of  pure 
tellurium. 

2.  Approximately    135   grams  of  tellurium   twice   distilled   in 

^oc.  cit. 


[19] 


3BOO 


4000 


4100 


33.  33 


37 


5- 


[20] 

hydrogen  were  dissolved  in  nitric  acid  and  evaporated  to  dryness 
twice  with  concentrated  hydrochloric  acid  to  remove  the  excess 
of  nitric  acid.  The  tellurium  tetrachloride  which  formed  was 
dissolved  in  the  least  possible  excess  of  hydrochloric  acid.  Twenty 
fractions  of  tellurium,  approximating  6.25  grams  each,  were  pre- 
cipitated from  this  solution  by  adding  hydrazine  hydrochloride. 
The  general  method  of  procedure  was  as  follows:  A  solution  of 
the  hydrazine  hydrochloride  was  added  to  the  tetrachloride  solu- 
tion ;  and  after  standing  overnight  at  a  temperature  of  about  50 
degrees  centigrade,  it  was  heated  to  boiling  to  complete  the  re- 
action. The  precipitated  tellurium  was  collected  on  a  hardened 
filter  paper  (which  had  been  previously  treated  with  hydrochloric 
acid)  and  washed  thoroughly,  first  with  hydrochloric  acid  ( I  to  2), 
then  with  ammonia-free  water,  and  finally  with  absolute  alcohol 
followed  by  concentrated  ether.  After  the  ether  was  removed 
by  suction,  the  tellurium  was  carefully  dried  in  an  oven  at  about 
75  degrees  centigrade.  The  various  fractions  were  preserved  in 
glass-stoppered  bottles.  The  temperature  at  which  the  reduction 
took  place  was  varied  somewhat.  But  so  long  as  it  was  allowed 
to  finish  at  boiling  temperature  it  seemed  to  make  no  difference 
whether  the  hydrazine  was  added  to  a  cold  or  hot  solution  except 
that  the  reduction  proceeded  more  rapidly  in  a  hot  solution. 

There  are  at  least  two  possible  reactions  when  tellurium  tetra- 
chloride is  reduced  by  hydrazine  hydrochloride.  Their  equations 
are: 

Te  C14+(NH2)2  2HCl  =  Te+N2+6HCl 

and  Te  Cl4+4  [(NH2)2  2HCl]  =  Te+2N2+4NH4  C1+SHC1. 

The  yield  of  reduced  tellurium  indicated  that  the  reaction  took 
place  almost  wholly  according  to  the  first  equation.  This  reaction 
tended  to  increase  the  excess  of  hydrochloric  acid  present  in  the 
solution.  But  this  tendency  was  overcome  by  the  water  intro- 
duced with  the  hydrazine,  and  in  making  the  fourth  reduction 
several  grams  of  tellurium  dioxide,  resulting  from  hydrolysis  of 
the  tetrachloride,  came  down  with  the  metallic  tellurium.  Each 
succeeding  fraction  was  likewise  accompanied  by  a  considerable 
amount  of  the  dioxide.  This  dioxide  was  washed  into  the  filtrate 
with  hot  hydrochloric  acid  ( I  to  2).  Electrodes  were  made  by  the 
method  previously  indicated  from  the  different  fractions  of  tel- 
lurium and  the  spectra  of  the  various  fractions  compared.  Ex- 


[21] 

ceedingly  careful  comparisons  of  the  first,  middle,  and  last  frac- 
tions were  made.  Two  series  were  chosen — i.  c.,  fractions  i, 
n,  and  19  in  the  first  series  and  2,  12,  and  20  in  the  second  series. 
After  several  trials,  almost  perfect  photographs  were  obtained  of 
these  spectra  one  above  the  other.  There  was  no  difference  be- 
tween these  spectra  except  that  the  two  copper  lines  mentioned 
above  came  out  in  the  last  fractions. 

3.  The  filtrate  from  the  twentieth  fraction  was  reduced  to  less 
than  3OOCC  by  evaporation,  and  the  usual  amount  of  hydrazine 
added,  and  fraction  21  was  thrown  down.  It  weighed  2.22  gr. 
The  filtrate  was  then  further  reduced  in  volume  and  fraction  22, 
of  0.5  gr.,  was  precipitated  from  the  boiling  solution  by  adding 
hydrazine.  A  twenty-third  fraction  consisted  of  a  very  slight 
precipitate,  which  was  lighter  in  color  and  more  finely  divided  than 
the  preceding  fractions.  Fractions  21  and  22  were  very  difficult 
to  fuse.  Thinking  that  they  might  be  mixed  with  the  dioxide,  frac- 
tion 21  was  washed  thoroughly  in  warm  hydrochloric  acid  ( i  to  2) , 
in  which  the  dioxide  is  soluble.  A  very  little  was  dissolved,  but 
the  remainder  seemed  as  difficultly  fusible  as  ever.  It  was  kept 
at  red  heat  for  twenty-five  or  thirty  minutes,  while  hydrogen 
passed  through  it,  and  it  was  finally  partly  fused.  Fraction  22 
was  mixed  with  a  part  of  fraction  20  and  heated  as  was  fraction  21. 
After  long-continued  heating,  it  was  partially  fused.  The  spectra 
of  fractions  21  and  22  were  compared  with  the  redistilled  tel- 
lurium and  with  the  middle  fractions — i.  c.,  9  and  12.  There 
was  no  difference  except  the  copper  lines  in  fractions  21  and 
22.  Fractions  21,  22,  and  23  were  then  treated  with  nitric 
acid  (sp.  gr.  1.25).  A  brownish  white  residue  remained,  which 
was  found  to  be  barium  sulphate  with  a  trace  of  tellurium.  The 
nitric  acid  solution  was  evaporated  to  dryness  three  times  with 
concentrated  hydrochloric  acid,  and  a  second  residue  (barium  sul- 
phate) remained  insoluble  in  hydrochloric  acid.  The  hydrochloric 
acid  solution  of  tellurium  tetrachloride  was  treated  with  hydrogen 
sulphide.  A  reddish  brown  color  resulted,  and  a  brownish  black 
precipitate  formed.  When  the  action  seemed  complete,  ammonia 
was  added  to  excess.  At.  first  the  mixture  became  milky,  and  a 
curdy  white  precipitate  formed  which  completely  hid  the  brownish 
black  precipitate.  This  white  precipitate  was  probably  tellurium 
dioxide.  The  mixture  then  darkened  and  the  precipitates  went 
into  solution.  (There  remained  undissolved  a  small  finely  divided 


[22] 

black  residue — residue  A).  The  solution  was  evaporated  nearly 
to  dryness  and  all  the  tellurium  was  precipitated  as  a  mixture  of 
metallic  tellurium  and  tellurous  sulphide,  and  some  ammonium 
salts  crystallized  out.  The  ammonium  salts  were  extracted  with 
water,  the  tellurium  mixture  was  then  boiled  with  concentrated 
hydrochloric  acid,  and  hydrogen  sulphide  was  evolved.  Tke  me- 
tallic tellurium  was  then  dissolved  in  warm  nitric  acid  and  the 
insoluble  residue  filtered  out,  dried,  and  treated  with  carbon  bi- 
sulphide, which  dissolved  the  sulphur.  The  remaining  residue  was 
soluble  in  nitric  acid  and  was  added  to  the  above  nitric  acid  solu- 
tion. This  nitric  acid  solution  was  evaporated  to  dryness  twice 
with  concentrated  hydrochloric  acid  and  taken  up  in  hydrochloric 
acid  and  precipitated  with  hydrazine  as  usual.  The  tellurium 
thus  precipitated  was  very  difficultly  fusible*  but  electrodes  were 
finally  secured — tellurium  Z.  The  spectrum  of  tellurium  Z  was 
compared  with  'that  of  pure  tellurium  —  i.  c.,  fraction  8  — 
and  a  number  of  barium  lines  were  found  in  spectrum  of  tel- 
lurium Z.  The  two  copper  lines  still  persisted  also.  Tellurium 
Z  was  dissolved  in  nitric  acid.  A  white  residue  remained  which 
proved  to  be  barium  sulphate.  The  solution  of  tellurium  Z  was 
evaporated  to  dryness  twice  with  concentrated  hydrochloric  acid 
and  taken  up  in  slight  excess  of  the  acid.  The  tellurium  was 
precipitated  by  passing  sulphur  dioxide  into  the  hot  solution, 
and  was  washed,  dried,  and  fused  as  usual.  It  was  perhaps  a 
little  more  difficultly  fusible  than  the  fractions  8,  9,  10,  etc. 
The  new  electrodes,  tellurium  Y,  were  compared  with  the  pure 
tellurium  of  fraction  8.  The  two  copper  lines  A32734  and 
A3246.8  were  found  in  tellurium  Y.  Otherwise  the  spectra  were 
identical. 

The  final  filtrate  (from  fraction  23)  was  evaporated  almost  to 
dryness.  It  yielded  several  grams  of  a  white  crystalline  substance 
which  proved  to  be  hydrazine  hydrochloride.  The  crystals  were 
removed  and  purified  by  recrystallization,  and  the  mother  liquors 
returned  to  the  filtrate,  which  was  then  evaporated  to  dryness  on 
a  steam  bath.  A  brownish  residue  remained  which  seemed  to  lack 
definite  crystalline  form,  and  had  an  odor  suggesting  organic  mat- 
ter. It  was  digested  thoroughly  with  concentrated  nitric  acid  and 
evaporated  to  dryness  three  times  over  a  low  flame.  The  color  of 
the  residue  was  changed  to  a  yellowish  brown,  and  small  bunches 
of  octahedra  crystals  were  present  in  it.  The  residue  was  digested 


[23] 

with  hot  water  and  the  insoluble  matter  filtered  out  and  dissolved 
in  nitric  acid  (sp.  gr.  1.25).  It  was  found  to  contain  considerable 
barium  and  traces  of  iron  aluminum  and  tellurium.  The  water 
solution  gave  a  greenish  yellow  crystalline  residue — rhombohedra 
and  hexagonal  pyramids.  Hydrogen  sulphide  in  an  acid  solution 
of  these  crystals  gave  a  brownish  color  and  finally  a  brownish 
black  precipitate  which  responded  to  the  tests  for  tellurium.  It- 
was  tested  carefully  for  copper  with  negative  results.  The  filtrate 
also  gave  doubtful  indications  of  iron.  A  trace  of  barium  was 
found  to  be  present.  The  barium  was  removed  from  the  entire 
residue  and  the  solution  evaporated  to  dryness.  A  greenish  yellow 
crystalline  residue  remained  behind  which  was  very  hygroscopic. 
It  was  dissolved  in  water  and  a  few  drops  of  hydrochloric  acid 
and  treated  with  ammonia  in  the  presence  of  ammonium  chloride. 
A  white  flocky,  semitransparent  precipitate  formed  which  ag- 
gregated on  boiling.  On  standing  overnight  the  precipitate 
changed  to  a  light  brownish  yellow  color.  The  filtrate  was  evap- 
orated to  dryness  and  heated  till  ammonium  salts  were  driven  off 
and  a  very  slight  brownish  residue  remained,  tinged  in  two  spots 
with  green.  The  precipitate  was  thoroughly  washed  and  dissolved 
in  nitric  acid,  resulting  in  a  slightly  yellowish  solution.  This  solu- 
tion— unknown  number  i — was  concentrated  and  its  spectrum 
photographed.  It  gave  a  number  of  calcium  and  copper  lines 
and  several  faint  lines  which  were  not  identified  at  this  time,  but 
later  proved  to  be  iron  and  silver  lines.  The  solution  was  evap- 
orated to  dryness,  the  residue  converted  into  a  chloride,  and  the 
presence  of  copper  was  indicated  by  the  ordinary  qualitative  tests. 
The  calcium  was  removed  as  oxalate  in  the  presence  of  acetic  acid. 
Ammonium  chloride  and  an  excess  of  ammonia  were  added  until 
a  blue  color  indicated  that  the  copper  had  gone  into  solution. 
There  was  a  slight  precipitate  similar  to  the  precipitate  whose 
spectrum  we  had  just  examined.  This  precipitate  was  thoroughly 
washed  and  dissolved  in  nitric  acid  and  included  in  solution  (un- 
known number  2)  described  below. 

Residue  A  (page  22)  was  dissolved  by  boiling  with  dilute  nitric 
acid  and  treated  with  ammonia  in  the  presence  of  an  ammonium 
salt.  A  white  flocky,  semitransparent  precipitate  formed.  It 
changed  in  color  to  a  light  yellowish  brown  on  standing.  This 
precipitate  was  thoroughly  washed  and  dissolved  in  nitric  acid 
and  included  in  solution,  unknown  number  2. 


[24] 

The  filtrate  from  residue  A  was  treated  with  sodium  hydroxide 
and  the  ammonia  boiled  off.  A  heavy  white  precipitate  formed, 
which  was  filtered  off  and  washed  thoroughly.  It  dissolved  in 
hydrochloric  acid  with  effervescence.  A  portion  of  the.  hydro- 
chloric acid  solution  gave  a  slight  muddy  color  with  hydrogen 
sulphide,  and  on  adding  ammonia  to  the  solution  saturated  with 
hydrogen  sulphide  a  slight  blackish  flocky  precipitate  appeared. 
Further  examination  showed  that  the  heavy  white  precipitate  was 
chiefly  calcium,  and  that  the  black  flocky  precipitate  contained  a 
trace  of  copper.  The  calcium  was  thrown  out,  as  the  oxalate, 
from  the  entire  hydrochloric  acid  solution,  an  excess  of  ammonia 
added,  and  the  solution  boiled.  A  slight  white  semitransparent 
precipitate  formed  which  changed  in  color  to  a  light  yellowish 
brown.  It  was  washed,  dissolved  in  dilute  nitric  acid,  and  included 
in  solution,  unknown  number  2. 

The  spectrum  of  the  solution  of  unknown  number  2  was  com- 
pared with  that  of  ammonium  nitrate  and  the  wave  lengths  of  the 
extra  lines  determined.  These  lines  indicated  positively  the  pres- 
ence of  calcium,  iron,  copper,  and  silver. 

4.  The  spectra  of  copper,  tellurium,  and  antimony  and  of  tel- 
lurium, thallium,  and  indium  were  carefully  compared.  Since  we 
had  only  salts  of  the  two  last-named  elements,  and  their  lines 
did  not  come  out  well,  their  study  was  discontinued. 

RESULTS  AND  CONCLUSIONS. 

The  spectrograph  has  fully  justified  the  claims  made  for  it  by 
Koethner  as  a  means  of  detecting  faint  traces  of  impurities  in 
chemical  substances.  It  has  also  proved  very  effective  in  identi- 
fying slight  residues  and  precipitates.  In  Koethner's  report  of 
his  spectrographic  work  he  called  attention  to  a  "shift"  in  the 
extreme  ultra-violet  lines  when  the  same  spectrum  was  photo- 
graphed twice  in  succession,  one  above  the  other,  on  the  same 
plate.  This  "shift"  was  investigated  and  found  to  be  only  an 
apparent  shift  due  to  an  improper  manipulation  of  the  apparatus. 
Such  a  shift  does  not  occur  and  is  impossible  with  our  new  form 
of  slit  cover  slide. 

The  tellurium  purified  in  this  laboratory  and  testing  C.  P.  by 
chemical  methods  was  found  to  contain  traces  of  copper,  iron,  and 
silver.  Kahlbaum  tellurium  was  also  found  to  contain  a  trace  of 
copper.  And  although  we  have  been  able  to  get  tellurium  free 


[25:J 

from  all  known  impurities  by  fractional  precipitation  with  hydra- 
zine  hydrochloride,  the  evidence  of  the  spectrograph  indicates 
that  we  have  not  brought  about  any  breaking  down  or  separation 
of  the  tellurium  into  parts  differing  in  properties.  The.  twenty 
fractions  showed  no  variations  in  their  spectra  except  the  appear- 
ance of  the  copper  lines  in  the  last  fractions. 

The  study  of  the  final  residues  has  not  developed  any  new  evi- 
dence on  the  tellurium  problem.  In  Flint's  discussions  of  his  final 
residues  he  mentioned  a  yellow  and  a  green  residue  which  he  said 
suggested  a  possible  contamination  with  iron  and  copper,  but  he 
could  not  find  even  the  slightest  trace  of  either  by  the  usual  tests. 
It  was  noted  above  that  the  residue  from  the  final  filtrate  had  a 
greenish  yellow  color,  and,  again,  that  the  filtrate  from  which  am- 
monia had  thrown  out  a  flocky,  semitransparent  precipitate  left  a 
slight  brownish  residue  tinged  with  green.  This  greenish  yellow 
residue  was  also  carefully  tested  by  the  usual  tests  for  iron  and 
copper,  and  gave  negative  results  for  copper  and  doubtful  indi- 
cations of  iron.  The  spectrograph,  however,  showed  the  presence 
of  both  these  impurities.  Flint  says  further  :  "When  an  excess  of 
ammonia  is  added  to  a  solution  of  the  green  substance  in  hydro- 
chloric acid,  the  precipitate  obtained  by  neutralization  of  the  acid 
is  not  completely  dissolved  by  the  excess  of  the  alkali.  The  liquid 
filtered  from  this  throws  out  a  black  substance  (apparently  tel- 
lurium) when  acidified  and  treated  with  stannous  chloride.  The 
precipitate  which  did  not  dissolve  in  trre  excess  of  ammonia,  when 
dissolved,  after  thorough  washing,  in  hydrochloric  acid,  gives  also 
a  black  precipitate  with  the  same  reagent."1  The  semitransparent 
precipitate  which  was  thrown  down  from  our  final  filtrate  was 
also  insoluble  in  an  excess  of  ammonia;  and  when  dissolved  in 
hydrochloric  acid,  after  thorough  washing,  threw  out  a  black  sub- 
stance when  treated  with  stannous  chloride.  The  filtrate  from 
the  ammonia  precipitate,  after  acidifying  with  hydrochloric  acid, 
was  slightly  darkened  when  treated  with  stannous  chloride.  From 
a  consideration  of  these  facts  it  seems  possible  and  even  probable 
that  Flint's  residues  did  contain  iron  and  copper,  but  in  such 
slight  traces  as  to  escape  detection  by  a  means  less  delicate  than 
the  spectrograph. 

Since  the  results  of  Flint  were  not  confirmed  b    his  method  in 


.  cit. 


[26] 

the  hands  of  Harcourt  and  Baker,  there  is  no  keen  disappointment 
that  the  results  of  the  method  set  forth  in  this  paper  likewise  do 
not  harmonize  with  his  results. 

The  fact  that  the  copper  which  came  down  in  the  last  fractions 
was  not  removed  by  two  subsequent  precipitations — one  by  hydra- 
zine  hydrochloride,  and  the  other  by  sulphur  dioxide — seems  to 
argue  for  a  large  number  of  fractions  as  against  single  complete 
precipitations  or  a  smaller  number  of  fractions  as  in  the  processes 
of  Gutbier1  and  Koethner.1 

The  presence  of  barium  and  calcium  in  the  residues  is  not  re- 
garded as  significant.  The  barium  was  from  the  hydrazine  hydro- 
chloride,  and  the  calcium  was  probably  an  accidental  impurity  or 
from  the  same  source. 

After  a  preliminary  comparison  of  the  ultra-violet  spectra  of 
tellurium,  copper,  and  antimony,  it  was  decided  that  the  coincident 
lines  were  not  of  sufficient  importance  to  study  them  further. 

A  careful  study  of  the  extreme  ultra-violet  spectrum  of  tellurium 
resulted  in  the  discovery  of  a  group  of  six  lines  of  shorter  wave 
length  than  any  tellurium  lines  found  in -Watt's  tables,  and  no 
record  of  their  previous  measurement  has  been  found.  They  are 
A2002.6,  A200I.8,  A2000.4,  AI997.6,  XI994.8,  and  AI993.8.  It  was 
also  found  that  a  number  of  strong  lines  given  in  Watt's  tables  as 
tellurium  lines  do  not  appear  in  the  spectrum  of  our  purified  tel- 
lurium. These  lines  belong  to  silver,  copper,  and  gold. 

In  conclusion,  the  tellurium  problem  remains  unsolved.  We 
have  mentioned  three  possible  solutions — namely:  (i)  Tellurium 
is  an  element,  though  abnormal;  (2)  tellurium  is  contaminated  by 
an  admixture  of  a  higher  homologue  of  tellurium  having  an  atom- 
ic weight  of  about  214;  (3)  tellurium  is,  like  didymium,  a  mixture 
of  two  substances  differing  but  little  in  atomic  weight  and  remark- 
ably similar  in  properties. 

We  have  only  added  another  link  to  the  chain  of  evidence  reach- 
ing back  over  forty  years  of  research  and  pointing  almost  uniform- 
ly toward  the  elementary  nature  of  tellurium.  However,  the  writer 
is  prone  to  believe  that  a  different  answer  will  be  forthcoming 
sooner  or  later.  The  higher  homologue  admixture  does  not  seem 
feasible  for  the  following  reasons :  If  this  higher  homologue — 
dvitellurium,  has  an  atomic  weight  of  214  and  the  correct  atomic 

^oc.  cit. 


[27] 

weight  of  pure  tellurium  is,  let  us  say,  125.5,  there  would  be  pres- 
ent only  about  two  and  one-fourth  per  cent  of  the  dvitellurium. 
It  is  believed  that  the  above-described  rigorous  treatment  of  135 
grams  of  material  containing  only  two  and  one-fourth  per  cent 
of  a  substance  as  different  from  true  tellurium  as  dvitellurium 
must  be  from  its  position  in  the  periodic  table  would  have  brought 
about  sufficient  separation  to  have  enabled  us  to  detect  it  by  means 
of  the  spectrograph. 

On  the  other  hand,  if  tellurium  is,  like  didymium,  a  mixture  of 
nearly  equal  parts  of  substances  differing  but  little  in  atomic 
weight  and  remarkably  similar  in  other  properties,  we  should  not 
expect  the  spectrograph  to  reveal  this  fact  to  us  without  more 
complete  fractionation.  And  the  writer  believes,  though  the  be- 
lief may  not  be  well  founded,  that  this  third  "possible  solution" 
suggests  the  direction  which  the  future  investigations  of  the  tel- 
lurium problem  should  take. 

THE  SPARK  SPECTRUM  OF  TELLURIUM. 

We  give  below  the  wave  lengths  of  the  lines  of  the  spark  spec- 
trum of  tellurium  as  we  have  found  them ;  also  previous  measure- 
ments by  Huggins1  and  by  Hartley  and  Adeney.1  It  was  stated 
above  that  a  number  of  lines  belonging  to  copper,  silver,  and  gold 
were  given  by  Hartley  and  Adeney  as  tellurium  lines.  The  wave 
lengths  of  these  lines,  with  the  elements  to  which  they  belong, 
will  be  given  opposite  the  corresponding  lines  in  Hartley  and 
Adeney's1  table.  The  intensities  range  from  i,  for  lines  easily 
visible,  to  10,  for  the  strongest  lines  in  the  tellurium  spectrum, 
o  is  used  for  lines  just  visible.  An  n  denotes  nebulous,  a  line  not 
sharply  defined;  s  denotes  sharp;  b  denotes  broad,  the  reading 
of  the  heaviest  part  being  given ;  sn  denotes  a  nebulous  line  which 
is  rather  sharply  defined.  After  some  of  the  lines  an  A  will  be 
seen  followed  by  a  question  mark,  indicating  that  it  is  possible 
that  this  line  is  an  air  line. 

1Watt's  "Index  of  Spectra,"  p.  136. 


[28] 


Other      Elements 

Other      Elements 

HUGGINS*  &  HAHT- 

OUR 

Present  in  Hart- 

HARTLBY  & 

OUR 

Present  in  Hart- 

Tellurium. 

ADBNBY. 

MEASUREMENTS. 

ley  &  Adeney's 

Tellurium. 

|| 

If 

Ijj 

Is 

Wave 

•*>  ° 

Wave 

Wave 

t 

Wave 

Wave 

*..  2 

Wave 

Length. 

•S  i 

Length. 

"•     r: 

Length. 

1 

Length. 

~  £ 

Length. 

—  * 

Length. 

S 

1  S 

IS 

1 

£  0 

Is  • 

I 

« 

- 

Bt 

a 

a 

a 

Hugging. 

4547-4 

3  n 

6600.0 

i  n 

§4544.0 

i  b 

6645.0 

6431.0 
6366.0 

4 

IOS 
I  S 

6641.5 
66045 
6481.6 
6433-4 
6363-5 

2  n 
i  n 
i  n 
4  sn 
2  n 

4487.0 
44So.o 
4436.0 
4400.0 

2sd 

2sd 

2Sd 
2sd 

4489-4 
4481.  S 
4436.2 
4102.4 
43900 

3" 
4n 

3" 

2  S 

A? 

6347.0 
6290.0 

I  n 

28 

6289.5 

2  n 

4378.0 
4364.5 

2sd 
2sd 

4377-4 

4363  s 

5  s 

6243.0 
6228.0 

3" 

38 

6242.4 
6227.6 

2  n 

2  n 

4353-0 
4324-6 

2Sd 

4356.2 
4326.8 

6160.4 

i  n 

4301-5 

6  sd 

4302.6 

5  s 

6042.0 
6010.0 
5995-0 

6sd 
6sd 
i  n 

toS^.o 
6043.0 
6010.0 
5993-6 

i  n 
3  n 
2  n 
i  n 

4292.7 

4287.3 
4274.4 
4*59-8 

4sd 

eld 

6sd 

4294.6 
42890 
4276.0 
4261.8 

3" 
3" 
4sn 
7  sn 

59700 

IO  SC 

5970-4 

5sn 

4222.1 

6sd 

422  r.o 

58 

59340 

Ssc 

5932-0 

4190.2 

3  s 

5854-0 

*-sf  ° 

4sc 
4sd 

5850.0 

3" 

4180.7 
4170.3 

2Sd 

4sd 

4181.4 
4172.0 

Snb 
2  nb 

*5Sol6 

4  no 

4  nd 

5825.2 
5804-4 

2  n 
t  n 

4162.5 
4I25-5 

3" 
3" 

57400 

10  SC 
28d 

S76I.5 
5753.8 
5742.2 

6  sn 
2  n 

4119.7 
4073.7 
4061.3 

4sd 

-•s.l 
6sd 

4119.8 
4073.8 
4061.5 

7sn 
4  s 

A? 

57o8.o 

10  SC 

6s 
4  sn 

A? 

4054-2 
4048.3 

6sd 
4sd 

4053-4 
4048.6 

4  sn 
3" 

5646.0 

IOSC 

5650  5 

7sn 

4011.6 

i  n 

56180 

4Sd 

5618.8 

2  sn 

4006.0 

Ssd 

4006.5 

4  8 

5575-0 

Ssc 

5575-0 

6  sn 

3985.2 

3  n 

54S6.0 

6sd 

5486.2 

5  sn 

3983.8 

6sd 

3982.2 

2  n 

5476-0 

6sd 

5476.0 

4sn 

3976.8 

2  n 

5447-0 

Ssc 

5449.4 

6  sn 

3970.2 

•>  n 

5409.0 
5366.0 

48d 

"  SC 

54io.5 

5369.5 

4  sn 

3968.6 
394S.O 

6sd 
6sd 

3947-5 

3n 

396S.3 

Ag 

5309.0 

6sd 

5310.8 

3» 

3932.5 

2sd 

3932-0 

3" 

5298-0 

2sd 

5299-0 

2  S 

390S.7 

3nd 

3907-8 

i  n 

5252.4 

3" 

3870.0 

i  n 

524L5 

2  n 

3841.3 

2sd 

3842-5 

6  sn 

5222.0 

Snc 

5230.0 

i  n 

3805.5 

i  n 

*5l/2.2 

2sd 

5174.5 

4  n 

3803.0 

4sd 

3801.5 

i  n 

*5I52.2 

6sd 

5I5I-4 

i  n 

i79X9 

2sd 

3797-4 

3" 

5038.0 

2nd 
4sd 

5  '33-6 
5062.0 
5038.0 

2  n 
I  n 

A? 

377^0 
3771.0 

4sd 
4sd 
4sd 

3789-0 
3776-4 

2  n 
2  n 

377'.  i 

Au 

4922.2 

i  n 

3765.0 

4sd 

3765-0 

2  n 

*489S.I 

2nd 

2  n 
4" 

3759-0 
3754-0 

4sd 
4sd 

3S 

3759-0 
3754-8 

Au 
Au 

4$S6.o 

3  n 

3750.0 

3  n 

4866.0 

4nd 

4868.0 

Ssn 

3737-2 

4n 

4842.8 

3  n 

3735.5 

Ssd 

4832.0 
4785-0 

2nd 
2nd 

4835-0 

4785.5 

4sn 

3736.2 
3716.0 

Ssd 
4sd 

3726.0 

2  n 

4769.0 

4  n 

3713.5 

i  n 

4737.1 

i  n 

3709.6 

i  n 

4731.6 

4  n 

3708.8 

o  n 

Hartley  & 

3698.7 

4sd 

Adeoey. 

3683-3 

4sd 

4707.5 
4693-0 

4sd 
4sd 

4706.8 

4sn 
5" 

A? 

3676-7 

4sd 

3679.0 

o  n 

§4664.0 

i  n 

4665  o 

3  n 

3670.4 

4sd 

3671.2 

o  n 

§4652.0 

i  n 

4656  2 

3  n 

3656.4 

4sd 

4602.0 

2  S.I 

46042 

5s 

36500 

3  s 

§4599-0 

i  n 

4S70-I 

3649.2  / 
3644-3  f 

6sd 

3<HS-S 

3S 

1  Loc.  cit. 

The  *  lines  are  from  Thalen-Watt's  tables. 


The  §  line*  are  from  Hugging-Watt'i  table*. 


[29] 


HARTLKY  & 
ADRNBY. 

OUR  MEASUREMENTS. 

Other      Elements 
Present  in  Hart- 
ley &  Adeney's 
Tellurium. 

HARTLKY  & 
ADENBY. 

OUR  MEASUREMENTS. 

Other      Elements 
"Present  in  Hart- 
ley &  Adeney's 
Tellurium. 

1  6 

Is 

1  i 

1  S 

Wave 

^0 

Wave 

£>  § 

Wave 

. 

Wave 

1?  8 

Wave 

i  S 

Wave 

Leugth. 

•a  <5 

Length. 

f| 

Length. 

I 

Ltngth. 

|  « 

Length. 

%  a 

Length. 

1 

ij 

|g 

S 

«>  g 

IS 

§ 

a 

K 

I 

•=  • 

-H 

36450 

3  s 

3168.5 

4sd 

3636.3 

4sd 

3160.4 

3  n 

3626.7 
3617.0 

6sd 

-  3627.0 
3617.4 

i  n 
4  sn 

3I5S.4 
3154.1 

2sd 

4sd 

3I53-4 

2  n 

3611.0 

4  sd 

3611.2 

2  n 

3'45-7 

4sd 

3601.7 

4  sd 

45 

3601.1 

Au 

2Sd 

3132.4 

45 

3599-6 

4sd 

3129.0 

i  n 

3594-5 
3589.4 

4sd 
4sd 

3593-0 

3584.0 

3" 
2  n 

3124.7 
3"9.5 
3107-5 

2Sd 

4  nd 
6sd 

3119.6 
3107  8 

3" 

355  J  -6 

Ssd 

3S5I.8 

6  sn 

3098.7 

4sd 

3098.2 

2  n 

3541.8 

4sd 

3s 

3541-7 

Au 

4sd 

3096.4 

4  n 

3533-1 

4sd 

5  sd 

3533-7 

Sb 

3088.0 

4  sd 

3090.0 

3n 

3522.0 

4sn 

3072.7 

6sd 

3073-0 

5". 

3520.3 

Ssd 

3520.3 

Sb 

3063-2 

2Sd 

3063.0 

§8 

2sd 

3052.8 

2Sd 

"3052.9 

411 

j 

Ssd 

34968 

6  sn 

3050.5 

3  n 

7 

2sd 

3484.0 

3sn 

3046.0 

Snc 

3047-4 

8  n 

3480.8 

4  sd 

3480.0 

2  n 

3022.1 

2  SC 

3023.2 

4n 

3474-4 

2sd 

3475-0 

3sn 

3016.6 

Ssd 

3018.0 

6n 

3465-5 

4  sd 

3466.0 

i  n 

3012.1 

4  sd 

3012.0 

4n 

3457-6  1 

4  n 

30055 

4  n 

3456.0 

Ssd 

3456.0  j 

4  n 

3004.1 

4  sd 

3004.2 

3  n 

3450-4 

26d 

3  s 

3450.4 

Cu 

2996.4 

4  sd 

2997-0 

3" 

3442.8 

5sn 

2988.8 

4sd 

2989.0 

2  n 

3441.2 

Ssd 

2976.2 

4  sd 

2977-4 

2  n 

3423-5 

o  n 

2975-5 

4sd 

2976.0 

3  s 

3422.2 

4sd 

2973-1 

2sd 

2973.8 

3s 

4sd 

2sd 

34H-7 

Sb 

2966.1 

Ssd 

2967.4 

6  n 

3407-5 

Ssd 

3407.8 

6  nb 

2960.3 

2  SC 

2960.4 

2  n 

3382.4 

IO  SC 

IO  SC 

3382.9 

Ag 

2956-3 

2sd 

2957.0 

3  n 

3374-1 
3362.4 

4sd 
Ssd 

3374-5 
3362.8 

3" 
6n 

2950.6 

2948.8 

2sd 

2Sd 

2950.8 
2948.8 

2  n 
2  n 

3352-1 

6sd 

3352-0 

3" 

2945-3 

2sd 

2946.0 

i  n 

3340.8 

i  n 

2940.8 

Ssd 

2941.4 

6sn 

3329.0 

6sd 

3329-I 

4  sn 

2937-7 

4sd 

33227 

4  sd 

3322.8 

2  n 

2932.5 

4  sd 

2932  s 

2  n 

33'5-S 

4sd 

3316.0 

2  n 

2928.1 

2sd 

2929.8 

2  n 

3307-I 

Ssc 

3308.0 

2  n 

2923.4 

4  sd 

3302.2 

2  n 

2918.9 

2sd 

2919.4 

5" 

2  n 

2905-9 

2  sd 

2906.8 

3289.6 

2  SC 

2901.9 

4sd 

4  s 

2002.  p 

Ag 

3283-0 

5sn 

8nd 

2895-4 

9  sn 

1 

3280.0  ) 

10  SC 

3281.2 

5sn 

10  SC 

3280.8 

Ag 

2893-3 
2877.4) 

2873.6  ; 

6sd 
2sd 
2sd 

2893.8 

4  n 
7sc 

5  s 

2877.1 
2873.6 

Sb 

Ag 

'. 

3278.4 

3  n 

2867.7' 

8nd 

2868.8 

8  sh 

3269.5 

3  n 

2859:9 

6sd 

2860.6 

4  n 

3266.8- 

5" 

2857-0 

8nd 

2857.9 

8  sn 

3264*6  j 

2sd 

2844.9 
28400 

6sd 
6  sd 

2846.4 
2841.0 

4  n 
6n 

3261.5 

3  n 

2836.9 

2Sd 

3256-3 

Ssd 

3257.4 

5sn 

2834.4 

2sd 

2835.0 

3sn 

3252.4 

5  sn 

2823.2 

6  sc 

3250.8 

4sd 

2818.8 

4  n; 

3246.8 

IO  SC 

TO  S 

3247.6 

Cu 

2815-3 

28d 

3242.  i 

4sd 

2813.0 

2Sd 

2812.0 

2  S 

3234-2  1 

4sd 

3232-8 

4  nb 

2799.1 

4sd 

3229.4  f 

2sd 

2795-5 

4sd 

27970 

4  n 

3221.8 
3217.6 

4sd 
4sd 

3aao.o 

3" 

2791.9 

Snd 

2793.2 
2778.0 

8n 
o  n 

3213-3 

4  sd 

3214.2 

3  n 

2776.8 

o  n 

A? 

3210.4 

2  sd 

3211.6 

3n! 

2768.6 

6sc 

2769-5 

8s 

3192.2 

4sc 

2766.5 

6sd 

2767.0 

2  n 

3188.1 

4sc 

3188.3 

3  n 

• 

2766.0 

4sc 

3-85-0 

4  n 

2758.8 

On 

3183-7 

2sd 

2756.0 

2  SC 

3174-4 

4  sc 

3I7C.2 

5s 

275  '-5 

2  nd 

2751-8 

o  n 

[30] 


HARTLEY  & 
ADENEY. 

OUR  MEASUREMENTS 

Other      Element* 
Present  in  Hart- 
ley ft  Adcney's 
Tellurium. 

HABTLI 
ADEN 

Other      Elements 
Present  in  Hart- 
ley ft  Adeney's 
Tellurium. 

tY. 

Wave 

•e    . 

Wave 

Is 

Wave 

Ware 

1| 

Wave 

1| 

Waqe 

Length. 

jl 

Length. 

f1 

Length 

I 

I 

Length. 

P 

Length. 

}1 

Length. 

j 

2745.0 

4sd 

2745-5 

Sn 

2490.8 

2  nd 

2  S 

3490.4 

Au 

2743.0 

48d 

2488.7 

2sd 

2  S 

3488.' 

Au 

2739-5 
2738.0 

4  sd 
4sd 

2740.0 
27370 

i  n 

2485.3 
2480.9 

2  nd 
2sd 

2480.6 

3S 

2  n 

2485.7 

Ag 

2733.2 

o  n 

2479.6 

2  nd 

2724.5 

Ssn 

2476.7 

2  nd 

2477.8 

i  n 

2723.2 

2  nd 

2473.2 

6sc 

2474.3 

i  n 

2720.7 

2Sd 

Ss 

2473.7 

A  ~ 

2718.0 
2713.0  ) 
2710.2  f 
2702.3  « 

2sd 

2sd 
8nd 

2sd 

2711.4 
2703.2 

6sc 
Sn 

2717.9 

Sb 

2469.0 
2462.0 
2460.2 

2452.8 

2  nd 

4  nd 
4  nd 
2  nd 

2469.8 
24S3.S 

Ss 
4s 
i  n 

2462.6 
2460.0 

5! 

2700.3  f 
2696.6 

2  sd 
6nd 

2697.5 

10 

Sn 

2701.3 

Cu 

2447.8 
3444-3 

6sd 
2  nd 

2445-0 

8s 
2  n 

2447.7 

Ag 

2694.1 

6nd 

2695.4 

2441.7 

2  SC 

6s 

2441.9 

Cu 

2690.2 

2sd 

2691.8 

3  n 

343S.O 

Ssc 

2438.6 

4  n 

3688.2 

2sd 

2689.0 

o  n 

2433.5 

i  n 

2683.2 

2nd 

2683.8 

4n 

24320 

2  nc 

2431.8 

6  sn 

2679.8 

2  nd 

2680.0 
2676.8 

4n 
i  n 

2428.2 

2  nd 

28C 

7s 

IOS 

2430.3 
2428.1 

Ag 

Au 

2674.6 

2  SC 

2sd 

2674.0 

Sb 

2426.7 

2  nd 

2426.4 

4  n 

2666.0 

4sd 

2666.0 

i  n 

2425.0 

4  nd 

2424.7 

Cu 

2661.6 

3  n 

3423.8 

i  n 

2659.4 

2bd 

2660.0 

4n 

2420.3 

2  nd 

2420.0 

4  s 

3657.1 

4nd 

3656.5 

2  n 

2418.5 

2  nd 

2418.? 

3" 

2653.2 

i  n 

2415.8 

i  n 

2648.7 
2647.0 

2  nd 
2  nd 

2649-5 
2647.6 

4n 

24J3.3 
2411.4 

Ssc 
6sc 

2411.8 

IO  S 

4  n 

34133 

Ag 

2642.3 
2637.0 
3634.7 

2  nd 
2sd 
6nd 

2642.5 
2637.5 
2635.4 

i  n 

4n 
Sn 

2403.7 
2400.0 

6nd 

"SC 

2403.7 
2397.0 

i: 

i  n 

2400.5 

Cu 

2630.5 

2  nd 

2631.3 

5  n 

3393.0 

i  n 

2627.8 

4sd 

2628.2 

2  n 

3392.8 

4  nd 

2392.6 

i  n 

2624.3 
2621.4 

4sd 
4sd 

2635.0 
2622.5 

3n 
i  n 

2390.7 
3386.3 

4  nd 
10  nc 

Ss 

IO  S 

2391.0 

Ag 

2617-4 

2  SC 

2S 

2617.6 

Au 

33S3.8 

10  nc 

2383.8 

10  s 

2613.7 

4sd 

6s 

2614.3 

A* 

2377-0 

3  nd 

5  s 

2377-1 

Cu 

2611.3 

4sd 

2612.3 

i  n 

2375.3 

3  nd 

2375.0 

3  n 

2604.4 

2  nd 

2605.4 

4  n 

2370.3 

Ssc 

IO  S 

23/0.6 

Cu 

2599.4 

2sd 

2599.0 

4n 

2367.S 

2  n 

2598.1 

2sd 

9sc 

2597.5 

Sb 

3364.7 

4  nd 

IOS 

2364.8 

Au 

25940 

2sd 

3362.8 

4  nd 

4» 

2362.8 

Ag 

2590.1 

2585.0 

2  nd 
3  nd 

aSSS.I 

3  n 

2359.8 

4  nd 

10 

j  2359-9 
1  2359.7 

Fe? 

2580.1 
2578.0 

2  nd 
2  nd 

2578.6 

2580.6 

Ag 

2358.6 
2357-0 

6sd 
4  nd 

2358.6 
23574 

2  n 

2577.0 

3  n 

2352.0 

7  gf| 

2574.8 

4sd 

2575-0 

i  n 

235'-  7 

2  nd 

235I-I 

3sn 

2572.4 

4  nd 

2572.4 

2  n 

23443 

2  nd 

2344.5 

2564*1 

2  nd 

3  n 

2567.2 
2564.6 

on 
on 

2340.3 
3336.8 

2  nd 
2  nd 

3$ 

3" 

2558.7 

2  nd 

3559.5 

2  n 

2332.0 

Ssd 

S  s 

2332.1 

Ag 

2549.7 

2  nd 

2550.2 

3  n 

2327.6 

3  n 

2543.7 
2536.8 
3533.8 

6sd 
2  nd 
2sd 

2543.5 

i  n 

2  S 

6 

2536.7 
2533.6 

Ag 

Au 

3325-5 
2321.0 

Ssd 

Ssc 

2320.4 

Ss 
Ss 
i  n 

2325.8 
3321.1 

A| 

2528.3 

Ssc 
3  nd 

2530.7 

8s 

2526.9 

Cu 

2317.8 

Ssc 

2316.8 

Ss 
i  n 

23I7.9 

Ag 

2525.6 

2  sd 

3s 

2525.2 

Cu 

23:0.1 

2  nd 

2310.2 

2  n 

2523.1 

i  n 

2308.8 

2  n 

2517.8 

i  n 

2303-7 

2  nd 

2303.1 

Cu 

3511.7 

i  n 

2301.1 

2  nd 

2300.8 

i  n 

2505.2 

6sd 

IO  S 
95 

2506.6 
25064 

Cu 

2297-5 

2nd 

2299.8 
2297.3 

i  n 
2  n 

2502.7 

2Sd 

3* 

2503.4 

Au 

3295.0 

6nc 

6s 

2295.3 

3u 

2500.0 

Ssn 

2291.8 

2  nd 

4  s 

2291.7 

Cu 

2498.6 

6nd 

2497.8 

Cu 

2288.6 

2  nd 

2288.5 

2  n 

2491.3 

2  SC 

2492.0 

3sc 

22806 

6r.d 

Ss 

2281.3 

Ag 

[31] 


Other      Elements 

Other     Element* 

HAHTLJEY  & 

OUR  MEASUREMENTS. 

Preient  in  Hart- 

HAKTLBY & 

OUR  MEASUREMENTS. 

Present  in  Hart- 

AliEMY. 

ley  &  Adeney's 

AD«N«Y. 

ley  &  Adeney'B 

Tellurium. 

Tellurium. 

1  i 

•w    . 
§3 

•9     . 

1-1 

Wave 

Length. 

•fl 

Wave 

Length. 

£g 

Wave 
Length. 

i 

Wave 
Length. 

Jf 

Wave 
Length. 

II 

Ware 

Length. 

i 

IS 

a 

JJ 

1 

N 

|S 

1s 

I 

2277.2 
2275.7 

6nd 
6nd 

6s 

Ss 

2277.3 

2275.8 

Ag 

Ag 

2159-7 
2149-7 

2  nd 
2  nd 

2160.0 

6  sn 

45 

2149.1 

Cu 

2272.5 

5" 

2147.8 

2  nc 

2147.6 

7  n 

2266.2 

6nc 

2266.0 

7sn 

2146.7 

2  nd 

2264.2 

2  nc 

2264.2 

Cu 

2143-3 

6  sn 

22604 

6nc 

2259-5 

S  sn 

21427 

2  nd 

2142.6 

3sn 

2256.6 

6nc 

2256.2 

7sn 

2136.5 

2  nd 

3s 

2136  I 

Cu 

2250.0 
2248.0 

6nd 
6sc 

2251.0 

2  n 
6s 
7s 

2250.2 
2248.0 

Ag 
Cu 

2135-0 
2125.5 

2nd 
2  nd 

2  S 

Ss 

2134-5 
2125.3 
2125.3 

Cu 

Au 
Cu 

2247.3 
2243-3 

6nc 
6  be 

7s 

2247.6 
2243.8 

Ag 
Cu 

2122.5 

2  nd 

2121.4 

3s 
3" 

2122.4 

Cu 

2240.7 

2nd 

2240.2 

3" 

2119.8 

3" 

2238.2 

3" 

2119.0 

2  nd 

4s 

2II9.3 

Ag 

2231.3 

2nc 

2230.9 

Ag 

21I6.S 

2  n 

2230.3 

2  nc 

3  D 

2230.5 

Cu 

2116.3 

2  nd 

2  S 

2116.3 

Cu 

2229.0 

2  nc 

3s 

2228.7 

Ag 

2113.3 

2  nd 

3  s 

2112.3 

Ag 

2226.8 

2  nd 

2227.4 

2  n 

2  S 

2II2.C 

Cu 

2223.2 

2  nd 

2223.2 

i  n 

2110.5 

2  nd 

9s 

2IIO.8 

Au 

2219.3 

6  be 

6  s 

f  2219.6 

\22l8.8 

Cu 
Cu 

2108.4 
2103.6 

2  nd 
2  nd 

2109.2 

2  n 

2  S 

2103.3 

Cu 

2216.0 

2  nc 

2216.3 

3" 

2100.2 

2  n 

2IOO.8 

i  n 

2215.0 

2  n 

20822 

7n 

22II.2 

6nd 

5  s 

22II.I 

Cu 

20SI.2 

2  n 

2209.5 

6nd 

22O9.O 

6  sn 

2078.5 

2  nd 

2  S 

2079.0 

Cu 

2207.4 

2  n 

2O72.O 

2  n 

2202.8 

2  nd 

3" 

2202.3 

Ag 

2050.8 

2  nd 

22OO.I 

2  nd 

3  s 

22OO.I 

Cu 

2039.2 

2  nd 

2196.5 
2192.2 
2189.7 

2  nd 
6nc 
6nd 

S.s 

2196.8 
2192.4 
2189.9 

Cu 

Cu 
Cu 

2032.7 

2  nd 

j  2OO2.O 

2  S 

2b 

3  sn 

2037.3 
2031.3 

Cu 
Cu 

2l86.9 

2  nd 

2186.8 

4sn 

(2001.3 

4sn 

2lS2.O 

2  nd 

I  S 

2l8l.3 

Cu 

2OOO.O 

2  sn 

2179.2 

6  nc 

5s 

2179-3 

Cu 

I997.S 

i  sn 

2175-3 

2  nd 

3I7S-Q 

J  '994-5 

3sn 

2167.2 

2  nd 

2167.4 

75 

1  1993-7 

i  sn 

2165.7 

2  nd 

4s 

2I66.I 

Ag 

1321 

SUMMARY. 

1.  The  quartz  prism  spectrograph  has  proven  a  very  efficient 
instrument  both  for  detecting  traces  of  impurities  and  for  wave 
length  determinations.    Its  efficiency  was  greatly  increased  by  our 
modification  of  the  slit  cover  slide. 

2.  The  occasional  shift  of  some  of  the  ultra-violet   lines   in 
Koethner's  work  has  been  accounted  for,  and  it  has  been  elimi- 
nated by  the  use  of  our  new  slit  cover  slide. 

3.  The  entire  spark  spectrum  of  tellurium  has  been  measured. 

4.  The  tellurium  purified  in  this  laboratory  by  fractional  precipi- 
tation with  sulphur  dioxide,  by  fractional  crystallization  of  the 
basic  nitrate,  and  by  twice  distilling  in  an  atmosphere  of  hydrogen 
has  been  found  to  contain  silver,  iron,  and  copper. 

5.  It  has  been  shown  that  Khalbaum  tellurium  contained  a  trace 
of  copper. 

6.  Six   new   tellurium   lines   have   been   found    having  wave 
lengths  shorter  than  any  tellurium  lines  recorded  in  Watt's  tables. 

7.  It  has  been  shown  that  the  tellurium  of  Hartley  and  Acleney 
contained  copper,  silver,  gold,  and  probably  antimony. 

8.  It  seems  very  probable  that  Flint's  colored  residues  contained 
copper  and  iron. 

9.  Fractional  precipitation  of  tellurium  from  a  hydrochloric  acid 
solution  of  tellurium  tetrachloride  with  hydrazine  hydrochloride 
has  not  resulted  in  any  decomposition  or  breaking  -down  of  the 
tellurium. 

10.  We  have  obtained  more  than  one  hundred  grams  of  tellurium 
free  from  all  known  impurities. 


PAT.  JAN.  21 ,1908 


69SV1 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


